Ottawa (Dunrobin), ON Canada

7 July 2004   10:28PM EST  (top)
24 June 2005   10:11PM EST  (bottom left)
13 July 2005   10:41PM EST  (bottom right)

My initial identification of this species was based on Covell (1984), and subsequently confirmed by Dr. J. Donald Lafontaine of Agriculture Canada, to whom my thanks.  Additional information has been drawn from Forbes, William T.M., The Lepidoptera of New York and Neighboring States, Primitive Forms, Microlepidoptera, Pyraloids, Bombyces (Ithaca, New York: Cornell University, 1923).

Synanthedon acerni is one of a dozen or so species of Synanthedon known to occur in the Ottawa area, and the only one of these regularly attracted to lights (Covell, 1984).  Its clear wings are characteristic of the Sesiidae.

In Synanthedon acerni the long narrow forewings are edged in near-black, with a black bar at about 2/3 the length of the wing.  The subterminal area of the forewing is yellow between the veins, most visible in the top photo above.  The clear hindwing is shorter, with black bar at the midpoint of the costa, but only slight dusting of yellow near the apex.  When the wings are closed, the hindwing bar is visible through the clear forewing, so that it looks like a single wing with two bars, as in the bottom right photo.   The wings and antennae may have a purplish sheen depending on the lighting.  There is a bright reddish orange tuft at the end of the abdomen.  Covell (1984) indicates a wingspan ranging from 18 to 25 mm.

According to Forbes (1923), the larva of Synanthedon acerni, known as the Maple Callus Borer, bores in the branches of maple trees, and causes gall-like swellings.  Forbes gives the adult moth flight season as June and July.

My records to date for Synanthedon acerni (each date representing "the night of") are in the table below: